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Abstract:

An integrally molded plastic part has a main body with an opening, and a
door connected to the main body via an integral hinge and snapping into a
closed position closing the opening. The door, at each of its two sides
extending away from the hinge, includes a stopping surface via which the
door, in its closed position, abuts against a supporting surface of the
main body, and a snap-in hook protruding from the stopping surface and
comprising a retaining surface which engages behind an edge of a flange
confining the supporting surface. A distance between the two retaining
surfaces as compared to a distance between the flanges confining the two
supporting surfaces decreases with increasing distance to the hinge,
whereas distances between the retaining and stopping surfaces as compared
to distances between the edges of the flanges and the supporting surfaces
increase with increasing distance to the hinge.

Claims:

1. An integrally molded plastic part, comprising: a main body with an
opening, and a door connected to the main body at one side of the opening
via an integral hinge and configured to snap into a closed position
closing the opening of the main body, wherein the door at each of its two
sides extending away from the hinge comprises a stopping surface via
which the door, in its closed position, abuts against a supporting
surface of the main body located at the circumference of the opening, and
a snap-in hook protruding from the respective stopping surface and
comprising a retaining surface which extends away from the hinge, and
which, with its rim, engages behind an edge of a flange confining the
respective supporting surface, and wherein a distance between the rims of
the two retaining surfaces at the two sides of the door measured in a
direction parallel to the hinge as compared to a distance between the
flanges confining the two supporting surfaces measured in a direction
parallel to the hinge decreases with increasing distance to the hinge,
whereas distances between the retaining surfaces and the stopping
surfaces as compared to distances between the edges of the flanges and
the supporting surfaces increase with increasing distance to the hinge.

2. The integrally molded plastic part of claim 1, wherein the edges of
the flanges confining the two supporting surfaces are parallel, and
wherein the rims of the two retaining surfaces are straight but enclose
an angle opening away from the hinge.

3. The plastic part of claim 1, wherein the snap-in hooks are L-shaped in
cross section.

4. The plastic part of claim 1, wherein the snap-in hooks have a constant
wall thickness.

5. The plastic part of claim 1, wherein the hinge defines a plurality of
bending lines about which the door can be swiveled relative to the main
body.

6. The plastic part of claim 5, wherein all bending lines are parallel.

7. The plastic part of claim 1, wherein the flanges confining the
supporting surfaces are oriented at an inclination angle to a direction
in which the door is closed about the hinge.

8. The plastic part of claim 1, wherein the door is configured to be
re-openable out of its closed position.

9. The plastic part of claim 1, wherein the door and areas of the main
part which are laterally adjacent to the door in the closed position of
the door are configured to guide air in an engine compartment of a motor
vehicle.

10. The plastic part of claim 1, wherein the door is configured to
provide access to an object arranged in an engine compartment of a motor
vehicle and covered by the door in the closed position of the door.

[0002] The present invention relates to an integrally molded plastic part
comprising a door snapping into a closed position.

[0003] The plastic part may particularly be a component of a motor
vehicle. Even more particularly, it may be a component located in the
motor compartment of a motor vehicle, like for example a component
guiding air to an air heat exchanger.

[0004] The door of the plastic part serves for providing access to a
further component located behind the plastic part, for example. For this
purpose, the door can be opened out of its closed position. After
accessing the further part, the door can again be brought into its closed
position.

PRIOR ART

[0005] In known molded plastic parts comprising a door snapping into a
closed position, the door, on both sides of a door hinge, in closing
direction about the door hinge, abuts against a supporting surface via a
stopping surface of the door. Simultaneously, the door, in lateral
direction, i.e. parallelly to the door hinge, engages behind edges of
flanges confining the supporting surfaces and extending away from the
door hinge via snap-in hooks protruding from its stopping surfaces and
also extending away from the door hinge. These snap-in hooks comprise
deviating surfaces at their front ends via which they are laterally
pressed in due to contact with the flanges confining the supporting
surfaces, until they snap in behind the edges of these flanges. These
deviating surfaces also guide the door into its place between the flanges
confining the two supporting surfaces on both sides of an opening in the
molded plastic part, which is closed by the door in the closed position
of the door.

[0006] The deviating surfaces of the snap-in hooks of the door of the
known plastic part have to be comparatively broad to fulfill their
desired function, and, as a consequence, the snap-in hooks have to be
comparatively high to securely guide the door into its closed position
even with tolerances occurring, which are often unavoidable with large
molded plastic parts. Further, it proves to be difficult to hold the door
without play in its closed position, on the one hand, and to nevertheless
be able to open the door out of its closed position without damaging its
snap-in hooks so that the door may snap into its closed position again,
on the other hand.

[0007] There still is a need for an integrally molded, i.e. one-piece
plastic part comprising a door snapping into a closed position, in which
the door, even with higher tolerances occurring, is securely guided into
its closed position and held in its closed position without play and in
which opening of the door out of its closed position is nevertheless
possible without damaging its snap-in hooks.

SUMMARY OF THE INVENTION

[0008] The present invention relates to an integrally molded plastic part
comprising a main body with an opening, and a door connected to the main
body at one side of the opening via an integral hinge and configured to
snap into a closed position closing the opening of the main body. The
door, at each of its two sides extending away from the hinge, comprises a
stopping surface via which the door, in its closed position, abuts
against a supporting surface of the main body located at the
circumference of the opening, and a snap-in hook protruding from the
respective stopping surface and comprising a retaining surface which
extends away from the hinge, and which, with its rim, engages behind an
edge of a flange confining the respective supporting surface. A distance
between the rims of the two retaining surfaces at the two sides of the
door measured in a direction parallel to the hinge as compared to a
distance between the flanges confining the two supporting surfaces
measured in a direction parallel to the hinge decreases with increasing
distance to the hinge, whereas distances between the retaining surfaces
and the stopping surfaces as compared to distances between the edges of
the flanges and the supporting surfaces increase with increasing distance
to the hinge.

[0009] Other features and advantages of the present invention will become
apparent to one with skill in the art upon examination of the following
drawings and the detailed description. It is intended that all such
additional features and advantages be included herein within the scope of
the present invention, as defined by the claims.

SHORT DESCRIPTION OF THE DRAWINGS

[0010] In the following, the present invention will be further explained
and described with reference to the attached drawings.

[0011] FIG. 1 is a back view of an integrally molded plastic part
comprising a door.

[0012] FIG. 2 is a cross-section through the integrally molded plastic
part along a line D-D depicted in FIG. 1 with a viewing direction
indicated in FIG. 1 by arrows.

[0013] FIG. 3 is a cross-section through the integrally molded plastic
part along a line E-E depicted in FIG. 1 with a viewing direction
indicated in FIG. 1 by arrows; and

[0014] FIG. 4 is a cross-section through the integrally molded plastic
part along a line F-F depicted in FIG. 1 with a viewing direction also
indicated in FIG. 1 by arrows.

DETAILED DESCRIPTION

[0015] In an integrally molded plastic part according to the present
invention comprising a door snapping into a closed position, wherein the
door at both sides or ends of a door hinge, in its closed position about
the door hinge, abuts against supporting surfaces via stopping surfaces
of the door, and, parallelly to the door hinge engages behind edges of
flanges confining the supporting surfaces and extending away from the
door hinge via retaining surfaces also extending away from the door hinge
and provided at snap-in hooks protruding from the stopping surfaces, a
distance of rims of the retaining surfaces in a direction parallel to the
door hinge, as compared to a distance of the flanges confining the
supporting surfaces also in a direction parallel to the door hinge,
decreases with increasing distance to the door hinge, whereas distances
of the retaining surfaces to the stopping surfaces, as compared to
distances of the edges of the flanges confining the supporting surfaces
to the supporting surfaces themselves, increase with increasing distance
to the door hinge.

[0016] The course of the rims of the retaining surfaces according to the
present invention, by which the snap-in hooks terminate behind the
flanges confining the supporting surfaces in the closed position of the
door, has the result that, during closing the door, during which the
areas of the snap-in hooks located closer to the door hinge engage
between the flanges confining the supporting surfaces at first, this
engagement is made particularly easy by the comparatively low distance of
the rims of the retaining surfaces in this area close to the door hinge.
Further, the door is automatically centered between the flanges confining
the supporting surfaces. In further closing the door, the snap-in hooks
further enter between the flanges confining the supporting surfaces,
wherein they are laterally compressed via the rims of the retaining
surfaces sliding along the flanges. No special deviating surfaces at the
snap-in hooks are required for this purpose. When the door reaches its
closed position, the rims of the retaining surfaces of the snap-in hooks
snap behind the edges of the flanges confining the supporting surfaces
due to the course or shape of the retaining surfaces and of the edges of
the flanges. In the closed position of the door, the retaining surfaces
tightly and preferably with some elastic force abut against the flanges
confining the supporting surfaces in those areas close to the door hinge.
Although the rims of the retaining surfaces only slightly engage behind
the edges of the flanges here, there is no danger that the door
unintentionally opens out of its closed position, because the rims of the
retaining surfaces engage behind the edges of the flanges to a larger
extent in the areas of the snap-in hooks farther away from the door
hinge. Due to the lower distance of the retaining surfaces from the
stopping surfaces in the areas of the snap-in hooks closer to the door
hinge, the stiffness of the snap-in hooks is higher in these areas than
in their areas farther away from the door hinge. As a result, the door is
held with a sufficiently high holding force in its closed position.
Nevertheless, the door can be opened without damaging its snap-in hooks
by overcoming this holding force, and the door may subsequently be closed
into its closed position again. Even if the door of the molded plastic
part according to the present invention may not be suited for being
opened and closed again very often, it allows for being opened and closed
some times without damaging its snap-in hooks.

[0017] The design of the snap-in hooks of the door of the molded plastic
part of the present invention appears to be unusual as their retaining
surfaces are not abutting against the flanges confining the supporting
surfaces where the rims of the retaining surfaces engage behind the edges
of the flanges to the farthest extent, whereas there, where such an
abutment is present, the retaining surfaces only engage behind the edges
of the flanges to a small extent. Nevertheless, the retaining surfaces of
the snap-in hooks of the door of the molded plastic part according to the
present invention have a function over their entire extension away from
the door hinge. Further, the design of the snap-in hooks may appear
unusual but it enables an easy manufacture of the molded plastic part
according to the present invention. Particularly, the snap-in hooks do
not need any additional deviation or guiding surfaces at their front
ends.

[0018] As defined above, it is not essential that the absolute distance of
the rims of the retaining surfaces in a direction parallel to the hinge
decreases with increasing distance to the hinge. It is only essential
that this distance decreases as compared to the distance of the flanges
confining the supporting surfaces in a direction parallel to the hinge
with increasing distance to the hinge. Similarly, it is not essential
that the absolute distances of the retaining surfaces to the stopping
surfaces increase with increasing distance to the door hinge. Instead, it
is essential that these distances increase as compared to the distances
of the flanges confining the supporting surfaces to the surfaces
themselves. I.e. the course of the retaining surfaces and their rims has
to be adjusted to the course of the flanges confining the supporting
surfaces. As long as the flanges confining the supporting surfaces,
however, run in parallel to each other, the rims of the retaining
surfaces display a V-shaped opening in a direction away from the door
hinge.

[0019] The snap-in hooks of the molded plastic part according to the
present invention may have a cross-section of a simple inverted L-shape,
as they do not need to have any deviation surfaces at their front ends,
as already explained. The width of the free limbs of the L-shaped snap-in
hooks may increase with increasing distance to the door hinge. Then, the
other limbs of the L-shaped snap-in hooks attached to the stopping
surfaces may increase in length with increasing distance to the door
hinge, but these limbs may keep a constant distance to the flanges
confining the supporting surfaces.

[0020] The snap-in hooks may have a constant wall thickness. In this case,
the rims of their retaining surfaces will nevertheless have a higher form
stiffness close to the door hinge than farther away from the door hinge
due to the dimensions of the snap-in hooks increasing with increasing
distance to the door hinge.

[0021] The door hinge of the door of the molded plastic part of the
present invention may have several target bending lines, i.e. it needs
not to be an integral hinge with a single target bending line. All target
bending lines are typically parallel. However, the target bending lines
may also be arranged at small angles. A softness of a guidance of the
door over its closing movement about the door hinge due to the plurality
of target bending lines is compensated for by the aligning and guiding
function of its snap-in hooks sliding along the flanges confining the
supporting surfaces.

[0022] It is particularly easy to get the snap-in hooks of the door of the
molded plastic part according to the present invention between the
flanges confining the supporting surfaces, if these flanges are oriented
at an inclination angle to the direction in which the door is closed.
They thus provide a funnel for the rims of the retaining surfaces of the
snap-in hooks. This also implicates that the flanges confining the
supporting surfaces are no simple rims of the supporting surfaces but run
at an angle to the supporting surfaces.

[0023] As already mentioned, the door of the molded plastic part according
to the present invention may be reopened out of its closed position
without damage, particularly without damaging its snap-in hooks.

[0024] In a particular embodiment of the molded plastic part according to
the present invention the door and the areas of the molded plastic part
neighboring the door in its closed position are designed as air guiding
surfaces. This embodiment of the molded plastic part may be configured to
be mounted in an engine compartment of a motor vehicle. Particularly, an
exchangeable object or an object which is only mounted after the molded
plastic part may then be arranged behind the door. This part is
accessible through the opened door. The door may also cover other parts
to which access is only necessary from time to time.

[0025] Now referring in greater detail to the drawings, an integrally
molded plastic part 1 which is partially shown in FIG. 1 includes a door
2 which is permanently connected to the remainder of the molded plastic
part 1 via a door hinge 3. In the area of the hinge 3 several target
bending lines 4 are defined in the molded plastic part 1, which together
define a hinge axis 5 of the door hinge 3. In FIG. 1, the door 2 is shown
in a closed position into which it can be snapped in with regard to the
remainder of the molded plastic part 1, and in which it closes an opening
in the remainder of the molding plastic part 1. When manufacturing the
plastic part 1 by injection molding, for example, the door 2 will be in
an open position. This may have the result that the door 2 is biased by a
bias force provided by the door hinge 3 out of its closed position
according to FIG. 1 into its original open position. This bias force,
however, will only be small and will have little effect on the function
of the molded plastic part 1 according to the present invention. In its
closed position, the door 2 abuts against supporting surfaces 7 of the
neighboring areas of the remainder of the plastic part 1 via stopping
surfaces 6. Further, snap-in hooks 8 protruding from the stopping
surfaces 6 engage behind flanges 9 confining the supporting surfaces 7.
The snap-in hooks 8 show a variation of their engagement behind the
flanges 9 with increasing distance to the door hinge 3. This variation of
the engagement is illustrated in FIGS. 2 to 4.

[0026] The cross-sections along lines D-D, E-E and F-F indicated in FIG.
1, which are shown in FIGS. 2 to 4 represent to an increasing distance of
the depicted snap-in hook 8 from the hinge axis 5 of the door hinge 3
according to FIG. 1. Close to the door hinge 3, a rim 10 of a retaining
surface 11 of the snap-in hook 8 only slightly engages behind the edge of
the flange 6 confining the neighboring supporting surface 7. On the other
hand, a distance of the retaining surface 11 to the stopping surface 6 is
comparatively small. Correspondingly, the snap-in hook 8 directly abuts
against the flange 9 with its retaining surface 11 in the cross-section
of FIG. 2. In medium distance of the snap-in hook 8 to the door hinge 3
according to FIG. 3, the engagement of the rim 10 of the retaining
surface 11 behind the flange 9 is farther than in FIG. 2. At the same
time, however, the distance of the retaining surface 11 to the stopping
surface 6 is also higher so that there is already a distance between the
edge of the flange 9 and the retaining surface 11. This tendency has
proceeded further in FIG. 4. I.e. the engagement of the rim 10 of the
retaining surface 11 behind the flange 9 is even farther. Further, the
distance between the edge of the flange 9 and the retaining surface 11
also increased.

[0027] During closing of the door 2 about the hinge axis 5 of the door
hinge 3 according to FIG. 1, the snap-in hooks 8 at first hit onto the
flanges 9 with their areas located most closely to the hinge axis 5, as
they correspond to FIG. 2. Due to the inclination of the flanges 9
oriented at an angle to the supporting surfaces 7, the door 2 with its
snap-in hooks 8 is guided between the flanges 9 and the snap-in hooks 8,
as a result, are aligned with regard to the flanges 9. During further
closing the door 2 until its stopping surfaces 6 abut against the
supporting surfaces 7, the snap-in hooks 8 also enter between and finally
behind the flanges 9 with their areas farther away from the door hinge 3
according to FIG. 1, which correspond to FIGS. 3 and 4. During this
movement, the snap-in hooks 8 are at first increasingly elastically bent
inwards until they snap behind the flanges 9. In the final closed
position of the door 2, the door 2 is held by the areas of the snap-in
hooks 8 close to the hinge axis 5 as depicted in FIG. 2, wherein the rims
10 abut against the edges of the flanges 9 with an elastic force. The
areas of the snap-in hooks farther away from the door hinge 2 as depicted
in FIGS. 3 and 4, which display an engagement of the retaining surfaces
11 farther behind the flanges 9, hold the door in its closed position,
even if higher forces are exerted to the door in opening direction.

[0028] Nevertheless, the door may be opened out of its closed position
according to FIG. 1 without damage by applying a higher force onto the
door which is sufficient to deform the snap-in hooks 8 again. The door
may, for example, be reopened to provide access to an object located
behind the door 2 in its closed position. Afterwards, the door 2 may be
closed again, wherein the snap-in hooks 8 again engage behind the flanges
9 confining the supporting surfaces 7.

[0029] In a particular embodiment example, the door 2 together with
neighboring areas of the molded plastic part 1 provide air guiding
surfaces 12 which, for example, guide air in the motor compartment of a
motor vehicle towards an air heat exchanger.

[0030] Many variations and modifications may be made to the preferred
embodiments of the invention without departing substantially from the
spirit and principles of the invention. All such modifications and
variations are intended to be included herein within the scope of the
present invention, as defined by the following claims.